// 二.基于以下代码完成下面的四个练习
const fp = require('lodash/fp')

// 数据
// horsepower 马力,dollar_value 价格, in_stock 库存
const cars = [
  {
    name: 'FERRARI FF',
    horsepoower: 660,
    dollar_value: 700000,
    in_stock: true
  },
  {
    name: 'Spyker C12 Zagato',
    horsepoower: 650,
    dollar_value: 648000,
    in_stock: false
  },
  {
    name: 'Jaguar XKR-S',
    horsepoower: 550,
    dollar_value: 132000,
    in_stock: false
  },
  {
    name: 'Audi R8',
    horsepoower: 525,
    dollar_value: 114200,
    in_stock: false
  },
  {
    name: 'Aston Martin One-77',
    horsepoower: 750,
    dollar_value: 1850000,
    in_stock: true
  },
  {
    name: 'Pagani Huayra',
    horsepoower: 700,
    dollar_value: 1300000,
    in_stock: false
  }
]

// 2.2使用帮助函数_average重构averageDollarValue,使用函数组合的方式实现
let _average = function (xs) {
    return fp.reduce(fp.add, 0, xs) / xs.length
} // <- 无须改动
let averageDollarValue = function (cars) {
    let dollar_values = fp.map(function (car) {
        return car.dollar_value
    }, cars)
    return _average(dollar_values)
}
console.log(averageDollarValue(cars))


// 重构后
let dollar_values = function (cars) {
  return fp.map(function (car) {
    return car.dollar_value
  }, cars)
}
let averageDollarValue_ = fp.flowRight(_average, dollar_values)
console.log(averageDollarValue_(cars))
